Bridge for steam-engine-exhaust nozzles



Patented May 2'2", i930 AUGSTINE R. AYEBS, OF CLEVELAND, CHIC BRIDGE FOR STEAM-ENGINE-EXHAUST NOZZLES Application filed January 10, 1927. Serial No. 160,265.

My invention relates to bridges for steam engine exhaust nozzlesand has for its object to provide a bridge ofthis kind which will produce as large an entraining surface as 5 possible while causing the least possible ob-` struction to the exhaust jet. j The purposes of placing a'bridge across the exhaust nozzle of a steam engine are to increase the velocity and also the entraining surface of the jet. These advantages are in part offset by the obstruction of the jet which causes a back pressure. y According to my invention the arms of the bridge are made relatively wide near the periphery of the nozzle bore and relatively narrow near the center thereof. The result is that the exhaust jet is broken up most eifectively near its periphery'where the increase in the entraining surface will have the greatest effect in increasing the draft, while at the center of the jet, where an in crease in surface probably has little if any effect, the obstruction caused by the bridge is `reduced as far as possible without sacrificing the streng-th of the bridge. In other words, the greatest obstruction to the jet is placed Where the resulting increase in entraining surface will be most effective, namely, near the periphery of the jet.

In the accompanying drawing in which l have shown one embodiment of my invention bv way of example Fig. l is a plan view of an exhaust nozzle provided with my bridge, and

Fig. 2 is a vertical section thereof.

The nozzle l is adapted to fit upon and be secured to the end of the exhaust pipe of a steam engine. ln the embodiment shown the bridge consists of four arms 2, the outer ends of which are secured to the nozzle by means of studs 3, though any other suitable securing means may be used. For most satisfactory results the number ofV arms should be small, and by a small number I mean not more than four. "The arms are tapered to a sharp edge 4 at the bottom to reduce their resistance to the steam jet as much as possible and their upper sides are wider near the periphery of the bore of the nozzlethan near their central juncture. In

the drawing the arms are shown uniformly tapered from the periphery of the nozzle bore to points near their juncture, and this is the most desirable form.

,The arms are joined at the center for strength Vand rigidity, but their width near the center is reduced as far as possible to decrease their resistance to the jet. The reduction in Width near the center does not materially weaken the arms because thestress is mostlyvertical. The vertical dimension of the arms can be increased without practical effect upon the resistance to the jet, because the increase in skin friction with such a small number of armsis unimportant. i c While the drawing shows a bridge set into the mouth of the nozzle, this construction is not essential to the invention. The bridge may equally well rest upon the top of the nozzle.

Having described my invention, I claim:

1. A bridge for a steam engine exhaust nozzle comprising a plurality of arms eX- tending from the center of the bore of the nozzle to the sides thereof, said arms being of greater width near the periphery of the bore than at the center thereof, the width and number of said arms being such that their combined area in a plane perpendicular to the path of the steam is considerably less than the unobstructed area in said plane.

2. A. bridge for a steam engine exhaust nozzle consisting of a small number of arms radiating from a central juncture of small area, said arms being relatively wide at their outer ends and tapering to a narrow Width at the center.

The foregoing specification signed at Cleveland, Ohio, this twenty-eighth day of December, 1926.

AUGUSTINE R. AYERS. 

